Find the measure of BAC

<BAC = 20°

Step-by-step explanation:

It is given in the question that all 9 triangle which are formed are congruent, which means that in all triangles, the angle which is formed at point A is same.

Which means 9 angles collectively can be written as 9 · <BAC

If we consider all the 9 triangles, we can see in the figure that it forms a semicircle.

A semicircle has a total sum of angles equal to 180°

So we can write that:

9 · <BAC = 180°

Simplify for <BAC

<BAC = 20°

b, i believe, but not sure.